Birthday Surprise
by Toonumbtofeel91
Summary: Based on an RPG, Blaise and Sebastian have a lovely arrangement. But when Sebastian learns he missed her birthday, despite her not caring, he decides to give her a special day. More explanation about the back story inside.
1. Chapter 1

**The back story for this is based off a multiple fandom RPG based off of The Mortal Instruments- Sebastian has brought people to New York to make an army and help him in the war. Everyone ends up at the Institute and they live there unless they join Sebastian. Then he puts them in a hotel. Sebastian and Blaise made an arrangement. She'll help him, if she gets what she needs, has a human to play with, and Sebastian sweetens the deal by offering good sex. It'll be three chapters. I wrote this as a birthday present for my friend, so happy birthday, Lissa 3**

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Sebastian made his way inside the house, unclasping his bracelet as he walked in the door. He found his present from Blaise to be quite useful. Especially with his realization this morning when he woke up. He did some things around the house, before going up to his room. Blaise will still sound asleep in his bed, her lack of clothing covered by the sheet that laid over her body. He set the stuff he brought with him aside, before crawling into bed with her.

Blaise's eyes fluttered open as she felt the bed shift, smiling some as she saw Sebastian laying next to him. It was apparent that he had been out; He was fully clothed. "Morning," she murmured, stretching some. "Where'd you go?" She asked.

Sebastian leaned over, pressing a kiss to her lips. "Morning. I figured out a reason you could have been pissed at me yesterday when I came over," He said, propping himself up on his elbow, looking at her.

Blaise's brow quirked in response. He'd thought she was mad at him the previous day when he asked her to come over because she'd been distracted and didn't seem as happy to see him when she answered the door. She asked him if she had a reason to be mad at him and he said she didn't. Now he was telling her that she had a reason to be? "What's that?" She asked.

"I realized that I missed your birthday. Between everything going on, and the fact I really couldn't go out, it slipped my mind," He said, giving her an apologetic look. "So, I wanted to make up for it," he said, a mischievous grin forming on his lips.

Blaise's brow went up higher. "I didn't really expect anything, which is why I didn't mention it," She answered. She had to admit, she was curious as to what he prepared to make up for it.

"Well you've been such a darling. Your birthday should be celebrated.. If I'd had more time, I would have thrown you the best birthday party a girl could imagine. But, we can have a party of our own. Just us," He replied, sitting up. He reached over to his bedside table, grabbing a small box, holding it out for her. "Part one," he presented.

Blaise shifted, holding the sheet up as sat up. She took the box and opened it, her mind running wild with curiosity. She opened the box slowly, looking to see what was in it. Inside was a silver pendant necklace; A crescent moon with a pentagram inside. There was a emerald jewel in the middle of the pentagram, her birthstone.

"That was actually a lot harder to find than I thought it'd be in New York," Sebastian said, looking to see her reaction. She seemed pretty stunned, unsure how to react. He knew it was a pretty big surprise, and he doubted she'd been expecting something personal. "I'm not sure if you're much of a Jewelry wearer.. But I figured you'd like it," he said.

"It's beautiful," She said, looking over at him, giving him a kiss. "Thank you," She said with a smile.

Sebastian had come to learn that she played down her emotions. But he could see in her eyes and in her smile that she did genuinely like it. "You're welcome," He said, shifting out of bed.

"Now onto part two, if you're ready," he said, offering a hand to her.

"Are we staying in the house, or going out?" She asked, unsure what she needed to dress for.

"In the house right now," He told her. She got out of bed, pulling on her underwear from last night, and grabbed his shirt, pulling it on. She'd agreed to move into the house to keep him company, but after their.. fun last night, they hadn't really had time to get her stuff from her hotel. He took her hand, going with her toward the kitchen and dining room. He had breakfast made, a variety of different things between pastries he had picked up while he was out, to fruit, eggs, and waffles. He was still learning what she liked, so he decided to go for variety.

"It still amazes me that you can cook," Blaise said with an amused smile.

"What'd you think I did? Go out every time I wanted food?" He asked, pulling out a chair for her. While he may not be the hearts and flowers type of guy, he could still be a gentleman with a special girl.

She sat down, giving him a smile as he sat down with her. "I didn't really think about it. Then again, I also wouldn't have guessed you lived in a big house alone either," She said with a shrug, starting to get some food.

"Not alone anymore," He winked as he got his own food. She laughed softly as they ate. "So I don't have any other plans 'till the end of the day, so if you want, we could go back to your hotel, and pack you up, then officially move you in here?" He offered while they ate.

"I'd like that," She said, sipping her drink. "Do those other plans today have something more to do with you making up for my birthday?" She asked, seemly out of curiosity

"That it does," He said. "Do you think me making up would just be a pretty necklace and breakfast?" He asked, though it was mostly a rhetorical question.

"Well then, I look forward to seeing what else you have planned," she told him, giving him a smile while they ate.

They finished up a little after and Sebastian cleaned up what they had used, putting away any left-overs. Blaise got ready while he did as much, putting on her cloths for the previous day and fixed her hair hat was a mix between bed head and sex hair. She came down afterward, ready to go.

Sebastian grabbed the bracelet Blaise had made for him. She found a magical way to mask his appearance and alter it so he could go out in public without detection. He wouldn't need it for being in her hotel room, or going in and out, but he figured it'd be better to have it in case they went anywhere else. They got into the car and he drove back into town, toward the hotel he'd been having her stay at. He pulled up, parking, and got out. He went with her inside, and up to her room.

She didn't really have too much to pack. Some cloths, some of her witch stuff, and things of entertainment. Blaise got changed into something clean before they started packing up. They put her clothes into a suitcase. He let her take care of her personal items in the bathroom, while he worked on packing up her books and other craft stuff. It only took a couple of hours to get it all done. She took the stuff out to put it in his car while he officially checked out. Once they were done, they got back into the car.

"Want to grab lunch before we head back?" He asked, looking over at her. He was still trying to buy some time until his plans for later. She nodded in response. He clipped on his bracelet so they could go someplace. They found a simple restaurant, going inside.

"Any hints to your plans for later?" Blaise asked while they looked over their menus, deciding what they wanted.

He shook his head. "Nope. I want it to be a surprise," He said with a smirk.

She made a face, still curious about what he had planned. She learned not to assume anything with him. He was always surprising her with different things, so she had no idea what to expect. The waiter came over, taking their orders and menus.

"So are you wanting to room with me, or do you want your own room at the house?" He asked. They'd talked about her moving in, and she accepted his offer, but they never discussed rooming ideas.

"Hmm.. I'm not sure," She said, thinking as she sipped her drink. She hadn't really thought about it. But then again, after she gave her answer, they'd ended up in bed..

"We could always set up a room for you, put your stuff in it, and you can switch off between which bed you sleep in," He offered. He knew she didn't mind sleeping with him after sex, and he even stayed with her a couple of times, but he wasn't sure what she really prefered.

"That could work," She agreed with a smile. They got their food shortly after, occupying themselves by eating and enjoying each others company. He paid for the meal once they were done, going back out to the car with her.

Once they got back to the house, he let her pick which room she wanted. There were quite a few spread around the house, and only one was occupied. She picked one down the hall from him. Enough distance not to be right on top of him, but close enough if she wanted to see him, she wouldn't have to go clear to the other side of the house. He helped her unpack, getting everything sorted. She could decorate it more at a later date, but at the moment they just wanted everything in the room.

"How much do you want to know what I have planned later," He asked, smirking over at her as they finished.

She made her way over to him, linking her fingers in his belt loops, giving him a seductive smile. "I am very curious, that's for sure," She said, looking up with her cloudy gray eyes.

"How curious?" He asked, looking down at him.

"Well.. I'd be very grateful," She said, pushing up against him.

"Mm, I do have an addition for your room.." He said, pulling her with him back to his room. Sebastian went to his closet, getting out a hanger with a black cover over it. He held it out to her.

Blaise rose a brow, taking it to the bed, and laid it out, unzipping the bag. She found a black strapless lace dress. It appeared like it'd hug her frame and go to the mid thigh. "It's pretty," She said, giving him a smile.

"I was hoping you'd wear it to dinner tonight," He said with a smirk. She looked over at him with a question look. "You wanted to go out to a nice place last night. I wanted our first date to be somewhere where you'd actually me about to see _me_, not the magic alter of me," He said. "But tonight.. If you'd like, we could actually go someplace nice," He offered.

"That sounds lovely," She said, zipping it back up, setting it aside, before she went over and gave him a long kiss. "Thank you." She wrapped her arms around his neck.  
He smiled. "You're welcome," He said, slipping his arms around her waist. "You know, we've still got some time to kill before we need to get ready.." He stated, running his fingers along her side.

"Mm.. Any ideas how to kill the time?" She asked, quirking a brow playfully.

"Hmm.. I have a few ideas," He said, leaning down, kissing her deeply. She returned it, leaning into him. "We could christen your new bed," He suggested, pulling back a little.

"Sounds like a good idea to me," She replied. He grinned in response. She grabbed her dress, bringing it with them as they went to her room. She hung it on her closet door, before making her way over to him.

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**The next chapter is rated M. It isn't required to be read to understand the third part of the storyline. Reviews make me happy. **


	2. Rated M

**This chapter doesn't need to be read to understand the story. It contains high sexual content. **

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She brought her lips to his, kissing him deeply. He pulled them back to the bed, sitting down. She straddled his lap as they continued their heated kiss. He pulled at her shirt, breaking the kiss long enough to take it off. His lips trailed along her neck as she began to unbutton his shirt, and he undid her bra, tossing it off to the side. His hands found their way to her breasts, squeezing and teasing them. She moaned out softly, her head tilted back. He shifted so she could push off his shirt, before moving them, laying her down on the bed. He pressed kisses along her neck, trailing them down her body while he started to unbutton and unzip her pants. His lips crossed her stomach while he started to pull down her pants and underwear. She moaned out again, her fingers running through his snowy hair. He teased her in kisses along her inner thigh, before he moved up to kiss her again.

"Condom in my back pocket," He murmured against her lips. He hated the things, but he'd rather use them than having the worlds most confusing child ever (being that he has demon, human, and angel in him, and that she is a witch.) She reached around him, squeezing his ass, before she got it out, setting it aside. Her hands trailed around to find his jean buttons, unzipping it. She pushed his pants down, bringing his boxers with it. His kissed down along her jawline as he tore open the condom packet, slipping it on. He nibbled on her neck while he positioned and moved into her.

She moaned out loudly as he did, pulling on his hair. He groaned out in pleasure against her neck, moving his hips with hers, sucking on her neck. He heard her breath hitch before it sped up. He was breathing just as heavily against her neck, making a dark purple mark of his claim on her. He was sure she'd have to cover it up later, unless she wanted to wear it proudly.

He changed his thrusts to be harder, bringing them both more pleasure. "Oh, Sebastian," She moaned out his name. He kissed her deeply, shifting them so she was on top. She adjusted to it, starting to move with him while they kissed passionately and heatedly. He moved his hands back to her breasts, squeezing them and ran his thumbs over her nipples. She continued to let out moaned of pleasure into his mouth. He increased his pace from under her before moving them in a sitting position. He kissed along her neck one more, going down to her breasts. His tongue flicked over one of her nipples while he continued to squeeze and massage them.

"Oh yes," She moaned even louder, and he could hear the fact she was rising. He felt her squeeze around him, and he groaned against her breast. "Mm, Blaise." He moved harder, biting gently at her nipple, enough to give her pleasure but not pain. Her moans continued to get louder and more shrill as he felt his own climax coming. He moved rougher, biting her nipple harder to mix between pain and pleasure which sent her over the edge. "Fuck, Sebastian," She nearly screamed and moaned at the top of her lungs. He could feel her find her release just as he started his climax. "Oh, Blaise," He groaned out, thrusting harder and faster as they rode it out together.

They were both breathing heavily as they laid back on her bed. "That was amazing," She said, trying to catch her breath.

"I agree," He said, giving her a kiss. He glanced at the clock. "If you want, we can take a joined shower," He said with a smirk.

"Mm, sounds sexy to me," She answered. They got up and he threw out the condom while she turned on the water. They got in, and both washed their own hair, switching in and out from under the water. He grabbed a washcloth putting some soap on it, starting to run it along her body. He admired her wet, soapy figure as he worked on cleaning her off. Her eyes closed and he could see the pleasure in her features. They shifted so she was under the water, rising off, before she returned the favor of washing him. He washed off after her, before he leaned down, kissing her.

"We still have a bit more time to kill before we really need to start getting ready.." He prompted. "Perhaps we should try something different, if you want to have some more fun," He offered.

"Mm, different how?" She asked. He started to trail kisses along her body again, before he shifted to his knees, his hands trailing along her thigh as he kissed even lower. Every now and then they'd touch and kiss down low during foreplay, but they never actually finished the job like that. His fingers trailed along her, returning to her thighs as his mouth reached it's destination. She leaned her back against the wall, letting out a soft moan. His tongue explored her folds, and he reached out, squeezing her ass. She inhaled deeply, her hands working through his wet hair. He sucked on a spot, which caused her to moan out again, pulling on his hair. His mouth vibrated against her in a small sound of pleasure from it, which in turn, pleasured her more. He continued to work his tongue over her. He moved a finger into her, causing her to let out a shrill moan again. He licked along her entrance, finding her g-spot. She nearly screamed in pleasure as he found it. He smirked, teasing his tongue over it, causing her hips to buckle with pleasure. He added a finger, rubbing her insides. "Oh fuck, Sebastian," She said. He licked over her g-spot once more, putting more pressure into it. He started to flick his tongue over it, making her pull on his hair, moaning out loudly. He could tell she was close. He rubbed her faster, licking over her fully, before going back to her magical spot. A little bit longer of him teasing his tongue over it and she moaned out loudly, it echoing against the bathroom walls as she climaxed.

He licked her up, before rising, and kissed her. "You have the sexiest moan ever," He told her, with a satisfied smirk.

"Mm. Now it's my turn to make you moan," She winked, seeing that he was still turned on. She pushed him against the wall, kissing along his neck. Her hand moved down to him, starting to stroke him. She continued until she'd made him all nice and errect again, before she moved to her knees in front of him, kissing his tip. She continued to move her hands along his shaft, as she ran her tongue over the tip, sucking on the tip. He let out a groan of pleasure as she did, stiff as could be. As her mouth started to go down farther, she moved her hand to his balls to play with them while she sucked him. After making sure he was as turned on and hard as he could possibly be, she started to deepthroat him, taking him all in her mouth, running her tongue over him as she did. She bobbed her head, licking and sucking on him like a sweet lollipop. He pulled on her hair and she moaned again him, causing his hips to flex in pleasure. She continued to suck him down to the edge, not even gagging. He had no idea if she'd done it before, but if she hadn't, she was definitely doing amazing for her first time. She squeezed his balls as her tongue explored him, licking from his base to his tip. She moved her hand back to his shaft, rubbing him while she sucked on each of his balls for a bit. She went back to deepthroating him and playing with his balls. He rose, feeling it climax. "I'm close," he told her, unsure if she'd want to finish him with his mouth or not. Nevertheless, she continued until he came into her mouth. She swallowed it, before kissing his tip, and got up.

He kissed her once more. "God that was sexy," He said, smirking at her.

"We'll have some more fun later, we need to get ready," She told him, giving him one last kiss, before she turned off the water, getting out.

"Promise?" He teased, getting out with her. He dried off, putting a towel around his waist. "Let me know when you're ready, gorgeous," He said, kissing her cheek, before going down to his room.


	3. Final part

**This is the last part of the story. Tell me what you guys think =)**

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Sebastian dried his hair, brushing it out, and shaved. He got dressed into black slacks, and a button up shirt. He put his shoes on, and since he hadn't heard from Blaise yet, he decided to see what was going on in the Mundie world.

He watched some of the TV before he heard Blaise call for him. "Sebastian, I need your help." Sebastian got up, turning off the TV before going down to her room. He found her almost totally ready, aside from the fact she was holding the dress up, unable to zip the back herself. "Zip me up?" She asked.

He went over to her, zipping up her dress. "Mm, I much prefer undressing and unzipping you," He teased, pressing a kiss to the side of her neck. Some of her hair was up, and the rest was down, laying over her shoulders. She'd put on some makeup, and wore black pumps. The dress fit her perfectly, hugging her in all the right spots.

"You can unzip it later," She said, kissing his cheek. She grabbed the box with the necklace he got her. "Can you help me put this on?" She asked.

He nodded, taking it out. She moved her hair out of the way and he put it around her throat, clasping the back. He let go of it and she let her hair down, turning toward him. "You look stunning," He told her.

"Thank you. You look pretty good yourself," She said with a smile.

"You ready to go?" He asked her. She nodded and he took her hand. Unfortunately he had to put back on his bracelet as they went out. "Originally I would have taken you someplace other than New York.. But I don't know of any portals, and my sister broke my portaling house.." He muttered. Not to mention that he had no idea where his teleportation rings had went.

"You have a sister?" She asked as they got in the car.

"Yeah. You probably saw her, if not met her, while you were living at the Institute. Shorty, small cute red head. Names Clary," he said.

Blaise gave him a glance at the word 'cute' but didn't comment. "I think I saw her. I didn't know you had a sister," she commented.

He shrugged. "She doesn't like me much. She's dating Jace last I heard, who is basically like my half brother. We were raised by the same man, but he's really my father," he said.

"Interesting," She murmured. They rarely actually talked about themselves when they were together. Then again, when they were together, it was mostly sex.. Now they were starting to get to know each other more.

"Weird enough, we grew up going by the same name; Jonathon Christopher. He shortened it to Jace. I changed mine," He said. Technically he'd just gotten attached to the name while pretending to be Sebastian Verlac, and Sebastian Morganstern just sounded weird.

"Well I think Sebastian suits you," She said with a smile.

He smiled back. "Definitely suits coming out of your lips when you're moaning it," He teased.

She laughed softly. "I'm glad you think so," She said.

"I do," He said, taking her hand and squeezed it. "What are you in the mood for to eat tonight?" He asked.

"Hmm.. French?" She asked, looking at him.

"Mm, I can think of something French I want, and it's not food.." He murmured, glancing at her.

She rolled her eyes at him. "Later."

He grinned in response. "Promise?" He teased again. She smacked his leg, shaking her head. "French food sounds good," He said, continuing to drive. He found a nice French restaurant, parking and got out, going around to get her door. He took her hand, going inside, and sat with her. They looked over their menus, while they waited.

A waiter came around asking for drink orders. He would have originally offered wine, but he was fairly certain she was underage, not that it mattered to him, but it did to people serving it. They ordered after the drinks were brought to them.  
"Are you enjoying yourself today?" He asked her, looking over at her.

She nodded. "I am. I'm definitely learning a lot about you today," she said.

"How so?" He asked, quirking a brow. He was wondering what all she had learned about him.

"You have a sister, you had a different name, you're good at oral, you taste good," She winked. "And you can be romantic when you want to be. Without all the cheesy mushy crap," She added.

Sebastian chuckled softly. "I told you, just because the.. other part of me is more dominant don't mean I don't feel at all. And you are quite special," he said. giving her a smile.

Blaise rose a brow in response, looking a little stunned. "Special? Special how?"

"Special like, I enjoy spending time with you," He said with a shrug. He wasn't very in touch with his feelings, so they were hard to talk about. But they were there. "I have the emotions, but I was raised to be detached from them. But at risk of sounding cheesy and mushy, it feels a little easier to be in touch with the feelings," He said, glancing at her to see her reaction. He didn't want to ruin the great arrangement they had, but she'd asked.

Blaise had been concerned about developing emotions, so this was news, and helped her feel better about that. She smiled some. "It does sound a little mushy, but it's nice to know," She said.

"Of course, that doesn't change what my favorite activity is," He said with a wink.

Blaise laughed softly, shaking her head. She didn't have time to respond since their food was brought over. They started eating in a comfortable silence. Once they were done, Sebastian took care of the bill, before going back out to the car.

"Should we go out somewhere else, or go back and have our own party?" Sebastian asked, looking at her.

"We went out last night. Let's have our own party at home," She said.

He nodded, taking off his bracelet, driving back home. He parked once they got there, getting out. He opened the door her her, walking inside. "Mm, what sort of fun should we have?" He asked.

"Hmm. Well, you could unzip me from this dres.. and we could christen your bed," She suggested with a smrik.

He grinned in response, leaning over and kissed her. "And this is why you're a chick I'd have feelings for," He said with a wink.

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**So I couldn't remember what happened with the portaling house, I just know Clary did something. I'm pretty sure Jace and Sebastian had rings that let them teleport, but I couldn't remember what happened to them.. **


End file.
